The use of fertilizers is essential for the good growth and the high production of crops. Of the basic nutrients that the plants need to have a healthy development, most of the crops and soils require large quantities of nitrogen (from NO3− or NH4+), phosphorous (from H2PO4−), and potassium (from K+) (Wichmann, W., et al, IFA World Fertilizer Use Manual). Such quantities of nitrogen, phosphorous and potassium are provided mainly in the form of mineral fertilizers, already processed from natural or chemically-produced minerals (K. F. Isherwood, 1998, Mineral Fertilizer Use and the Environment, United Nations Environmental Programme Technical Report No. 26). The development and use of the mineral fertilizers since the 1940's have allowed significant increases in the production of the crops.
The damaging effects of mineral fertilizers has been recognized in recent years, despite the importance of such fertilizers. The challenge will be to use mineral fertilizers with more efficiency, and the intergrated management systems of the production provide a path toward rationalization in the use of the inputs. (Fertilizer and the future, by Louise O. Fresco, Assistant Director-General, FAO Agriculture Department,).
The mineral fertilizers sometimes damage the soil. For example, excessive use of chemically synthesized nitrogen can inhibit the natural activity of the microorganisms responsible for adjusting the nitrogen and, therefore, diminish the natural fertility of the soil. The extensive use of mineral fertilizers can cause contamination. For example, the loss of nitrogen and phosphate by the fertilizers due to erosion could contaminate soils and underground waters.
In the search for a solution to these problems, some agricultural engineers have again started the use of organic fertilizers and fertilizers consisting of a mixture of minerals and organics. The organic-minerals fertilizers are produced by combining some minerals with organic matter coming mainly from plants. Engineers have had very satisfactory results as to the enrichment of the plants and the soil.
Today, the organic fertilizers and the organic-minerals fertilizers can be made from various raw materials. Some of the first materials used were municipal organic residuals, due to their low cost and great macronutrients content, such as in the case of the U.S. Pat. Nos. 6,828,137 and 6,352,569. Other organic-based fertilizers used manure from cows, horses, chickens, lambs or pigs, as in U.S. Pat. No. 6,852,142. Although the organic matter coming directly from plants is one of the most abundant, few fertilizers use this source as the base of their formulation. The present invention may use in the production of a fertilizer the sabila as one source of organic matter, in addition to other nutrients, for its production.